1. Technical Field
This invention relates to wireless telephones, and has particular relation to antenna architecture for multiple band wireless telephones.
2. Background Art
Wireless telephones have long had to operate in multiple frequency bands. The older cellular telephones operate at 800 MHz, while the more modern PCS (Personal Communication System) telephones operate at 1900 MHz. This could be done with a single antenna, operating as a quarter-wavelength antenna in the first band and as a half-wavelength band in the second. As additional features become available, however, additional antennas must be used. This is undesirable, since it adds to the weight and bulk of what is intended to be a lightweight, compact, and (most importantly) portable productxe2x80x94a wireless telephone.
Applicants have overcome the limitations of the prior art, at least where the additional features are GPS and Bluetooth.
GPS is the Global Positioning System. A ground-based receiver receives precisely timed signals from several satellites. Each satellite has a precisely known position, a code for which is also included in the signal. By noting the time (and the differences in time) at which each signal is received, the receiver can calculate its own position. GPS operates at 1575 MHz.
The present invention provides wireless telephone, GPS, and Bluetooth capabilities in a single device with a single external antenna. Three embodiments are shown.
In the first embodiment, the telephone is designed to operate in only one telephone band. The external antenna is tuned for a multi-band response to access both telephone and GPS. A diplexer or electronic switch separates the telephone and GPS signals. An internal antenna is used for Bluetooth.
In the second embodiment, the telephone is designed to work in two telephone bands. The external antenna is used for both telephone bands. A single internal antenna is used for GPS and Bluetooth, with a similar diplexer or electronic switch.
The third embodiment is similar to the second, but uses two internal antennas, one for GPS and the other for Bluetooth. The diplexer or electronic switch is omitted.